The present invention relates to the machining of metals, particularly to machining of metals by high power-density beams, and more particularly to an apparatus and method for machining of metals using a conventional (non-pulsed) electron beam machine combined with a magnetic lensing system and beam shaping and rotating control electronics.
Applying high power-density beams to the machining of metals has been primarily performed using pulsed laser technology. Pulsed laser technology is commonly used for cutting and welding of relatively thin materials with numerous commercial applications. Applications also exist for laser drilled holes in the automotive and aerospace industries. However, laser drilling is limited to small diameter holes (typically less than 250 .mu.m) in thin sheets (&lt;1 mm) and the process is somewhat slow, requiring many pulses to form each hole.
Presently there is interest in pulsed electron beam (EB) drilling of holes because of the potential for a higher drilling rate and the ability to drill wider holes (up to 1,000 .mu.m). Pulsed EB cutting has also been proposed. However, these methods require the development of fast bias transformers and power circuits to pulse the beam and successfully vaporize and remove material from the drilled hole or channel being cut. Thus, there is a need for EB machining that does not require these fast bias transformers and associated power circuits, thus eliminating the need for fast bias pulsing technology for EB machining. The present invention satisfies the above-mentioned need by providing an apparatus and method for EB machining (drilling, cutting, and welding) that can use conventional EB guns, power supplies, and welding machine technology without the use of the fast bias pulsing technology. Basically, the invention involves the use of conventional (non-pulsed) EB machines in combination with a magnetic lensing (EB optics) system, and beam shaping and rotating control electronics, which can produce deeper and wider drill holes than can be produced by pulsed laser technology while at the same time maintaining the high-power-density advantages of the laser process.